共查询到20条相似文献,搜索用时 109 毫秒
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全息波导显示系统中输出光栅的衍射效率、位置和长度对整个显示系统的光强输出均匀性及能量利用率有重要的影响.通常输出光强均匀性由输出光栅的衍射效率决定,能量利用率受多重光栅的位置和长度影响.本文以中心视场光束的输出光强均匀为目的,对相应输出光栅衍射效率的位置分布进行优化与曲线拟合,得到输出光栅衍射效率随输出位置连续递增的分布曲线,并应用到所有视场光束.计算结果表明,相比于传统阶梯状衍射效率分布输出光栅,全息波导显示系统中采用具有连续衍射效率分布输出光栅时的光强输出均匀性得到明显提升.针对部分衍射光束未能进入出瞳的现象,提出错位优化法,按照出瞳大小和使用距离优化各重输出光栅的位置和尺寸,减小了光栅的无效衍射区域,提高了出瞳范围内的能量利用率. 相似文献
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针对结构紧凑的部分端面泵浦混合腔板条激光放大器,研究了泵浦匀化对其输出激光光束质量的改善作用。基于ZEMAX仿真软件,设计并对比分析了直接成像和波导匀化后再成像两种泵浦耦合方式对激光二极管阵列慢轴(晶体宽度)方向光强分布均匀性的影响,发现波导匀化后泵浦均匀性得到明显提升且激光二极管阵列发光坏点对泵浦成像的影响得以弱化。进一步实验验证了泵浦匀化对Innoslab激光放大器性能的改善作用:波导匀化后慢轴方向泵浦均匀度从90.6%提高到95.4%,进而使3通放大后输出激光光束质量因子M2从2.41提升到1.55,并且有效抑制了多通放大腔内的自激振荡。 相似文献
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在曝光线宽为90nm节点的投影光刻机照明系统中,针对准分子激光光源扩束后出射光束均匀性较差的问题,用高斯光束边缘叠加能够提高均匀性的原理对反射式扩束单元进行了分析。结果表明,平行反射式扩束单元出射光束之间叠加尺寸与反射板某区域透射率存在矛盾,制约了照明光束均匀性的提高。为此,提出了非平行反射扩束镜组,推导了出射光束尺寸、叠加子光束个数与两反射镜楔角之间的关系式,确定了楔角的取值范围和扩束单元的结构形式。通过建模分析,验证了设计的扩束单元在实现光束一维扩束的同时,不仅减小了叠加光束的干涉散斑效应,还提高了光束均匀性。 相似文献
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《物理学报》2021,(15)
提出一种基于阶梯相位调制的窄谱激光主动照明方法,利用阶梯型相位调制器对窄谱激光进行相位调制,提高照明激光到达目标处的光斑均匀性和稳定性.建立了窄谱激光阶梯相位调制和照明激光远场光斑均匀性的理论模型,搭建了光束经过1.8 km水平传输的窄谱激光主动照明实验平台,通过5阶梯相位调制器对0.05 nm线宽的照明激光进行相位调制,实现了照明激光远场光斑匀化实验.实验结果表明,通过5阶梯相位调制器进行相位调制后,远场光斑包含57%能量区域的空间闪烁率从0.73改善到0.33,中心光强时间闪烁指数从0.38改善到0.14,照明激光远场光斑均匀性和稳定性都得到明显提升. 相似文献
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以半经典密度矩阵理论和分子振动弛豫理论为基础,研究添加适当比例缓冲气体与适当减小波导芯径对光抽运太赫兹激光器输出光强的影响.计算结果表明,加入适当比例缓冲气体或适当减小波导的芯径均能提高太赫兹激光的输出光强;同时优化两个参数能进一步提高抽运激光能量转化为太赫兹激光能量的效率,延长工作腔中的有效激活区,延缓抽运饱和效应的出现,提高太赫兹激光输出光强.该研究对提高光抽运太赫兹激光器的能量转化效率、提高光抽运太赫兹激光器的输出功率及实现光抽运太赫兹激光器的小型化有重要的指导意义. 相似文献
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详细研究了准分子激光光束均匀性的各项评价指标,加工窗口描述了加工任务本身对光束均匀度的要求;能量分数回答了具体加工窗口即均匀度要求下的能量利用率问题;平顶因子则描述了整个光斑能量分布范围内的均匀性问题。利用激光波面分析仪对不同均匀器所获得的均匀光束进行评价比较,蝇眼透镜均匀器能量利用率高,整个光斑内的均匀效果好,但最佳均匀截面的位置动态范围小;组合棱镜均匀器均匀截面动态范围大,但整体均匀效量较差。 相似文献
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XeCl准分子激光光束均匀器及其应用 总被引:10,自引:0,他引:10
采用光束均匀器,改善XeCl准分子激光器输出光束强度的分布,其起伏优于2%,用这一装置测量了C60薄膜的刻蚀阈值,并完成了准分子激光改变C60薄膜电导率的实验研究。 相似文献
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We have reshaped the TEM00 beam emitted by a diode-pumped Nd-Yag laser by means of an optical homogenizer with zoom. The laser beam, first enlarged up to a size of (100 × 37.5) mm2, is homogenized and resized to a final dimension continuously adjustable from (130 × 4.5) mm2 up to (130 × 52) mm2. We measured the plateau uniformity, the root mean square fluctuation and the edge steepness of the beam according to the ISO standard definitions, showing a poor reliability of the above parameter values due to the definitions themselves, and propose an amendment to overcome this problem. We obtained a very sharp edge steepness, but the spatial coherence of the laser beam put a lower limit to the high-frequency intensity fluctuations on the plateau region of the homogenized beam. Finally, we discuss the optimum homogenizer design for spatially coherent laser beams, including the depth of focus issue. 相似文献
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Observing Nanometre Scale Particles with Light Scattering for Manipulation Using Optical Tweezers 下载免费PDF全文
Nanometre-scale particles can be manipulated using optical tweezers, but cannot be directly observed. We present a simple method that nanoparticles can be directly observed using optical tweezers combined with dark field microscopy. A laser beam perpendicular to a tightly focused laser beam for trap illuminates specimen and does not enter objective, nanoparticles in focal plane all can be directly observed in dark field because of light scattering. It is implemented that the polystyrene beads of diameter lOOnm can be directly observed and trapped. 相似文献
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Yung-Neng Hsiao Hau-Ping Wu Cheng-Huan Chen Yu-Chung Lin Min-Kai Lee Sung-Ho Liu 《Optical Review》2014,21(5):715-718
A laser beam shaping architecture based on a microlens array homogenizer has been exploited, in which the interference effect due to the coherency of the laser source deteriorates the uniformity. Moving diffusers have been considered as an effective way of averaging out the interference pattern. Because the uniformity is required in the line direction only, a one-dimensional reflective-type diffuser with a well-controlled diffusion angle has been proposed and prototyped. The diffuser is attached onto a rotating cylinder for movement in operation. The experiment demonstrates the effectiveness of the scheme, and a line beam with a uniformity of up to 92% has been achieved. 相似文献
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为了提升高功率固体激光器中激光二极管(LD)面阵抽运场性能,采用几何光学和数理统计分析的方法,建立了基于微透镜阵列匀束的LD面阵抽运耦合系统的数学与物理模型,对微透镜阵列参数与最终耦合输出抽运场参数之间的关系进行分析,明确了微透镜单元F数、微透镜通光单元数以及微透镜阵列空间周期参数的设计原则.经实验测试,优化设计完成的LD面阵抽运耦合系统光场不均匀度为7.9%,耦合效率为90.7%. 相似文献
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Laser induced backside wet etching combined with the diffractive gray tone phase mask has been used for the fabrication of a micro-lens array with a single lens diameter of 1 mm and a micro-prism in quartz. The micro-lens array was tested as beam homogenizer for high power XeCl excimer laser yielding a clear improvement in the quality of the laser beam.The optimum fluence range for fabrication of micro-lenses by laser induced backside wet etching using 1.4 M pyrene in THF solution and 308 nm irradiation wavelength is 1-1.6 J/cm2. The etching mechanisms of LIBWE are based on a combination of pressure and temperature jumps at quartz-liquid interface. 相似文献
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Wide-angle irradiation is achieved in laser photocoagulation treatment by means of a fibre bundle. The laser transmission system consists of multiple quartz fibres, the input ends of which are aligned and driven by a stepper motor across a high-power laser beam. The output ends are arranged in a hexagonal close-packed array from which the diverging laser beam successively irradiates different parts of a lesion without the use of a mechanical scan over the lesion. This fibre bundle scanner is useful for the treatment of widely spread skin lesions such as port wine stains. 相似文献
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T. Schmidt-Uhlig P. Karlitschek G. Marowsky Y. Sano 《Applied physics. B, Lasers and optics》2001,72(2):183-186
The feasibility of transmitting 20 MW, 5 ns laser pulses from a frequency doubled Nd:YAG laser through a standard 1500 μm
multi mode optical fiber is demonstrated. A new coupling scheme employing an optical homogenizer prevents breakdown in air
without the use of a vacuum chamber. At the same time a very homogeneous flat top beam profile on the fiber surface is achieved.
The new scheme therefore clearly simplifies fiber coupling of high power laser pulses. Experiments on the delivery of more
than 20000 pulses with 110 mJ mean energy without fiber damage have been performed.
Received: 2 August 2000 / Revised version: 18 August 2000 / Published online: 22 November 2000 相似文献